白桦脂酸对HepG2细胞的诱导凋亡作用及其机制

为研究白桦脂酸对人的HepG2细胞的凋亡作用及其机制。采用不同质量浓度的白桦脂酸处理HepG2细胞,MTT法测定白桦脂酸对HepG2细胞增殖影响;流式细胞术Annexin V-FITC/PI双染法检测细胞凋亡,PI单染法检测细胞周期,罗丹明123检测线粒体膜电位。MTT分析表明,白桦脂酸可抑制HepG2细胞增殖并呈剂量依赖关系。白桦脂酸对HepG2细胞24,48,72 h的半抑制质量浓度IC_(50)分别为52,26,17.5μg/mL。流式细胞仪检测结果表明,用20,30,40μg/mL的白桦脂酸分别处理48 h,总凋亡率分别为49.82%,55.575%,57.46%。细胞周期结果表明,随着白桦脂酸质量浓度的增加,G1期的细胞比例下降,S期的细胞比例增加,说明出现S期的阻滞。用质量浓度分别为20,40,80μg/mL的白桦脂酸处理的各组线粒体膜电位分别为83.63,73.63,64.3,与对照组89.25相比,均明显降低,这表明白桦脂酸诱导细胞凋亡可能与线粒体途径有关。白桦脂酸可抑制肝癌HepG2细胞的增值,诱导HepG2细胞凋亡,这一机制可能与线粒体途径有关,通过将细胞阻滞在S期来实现。     

紫甘薯汁抗肿瘤活性及诱导人肝癌细胞HepG2凋亡机制研究

目的:研究紫甘薯汁的抗肿瘤活性及其诱导肝癌细胞HepG2凋亡机制。方法:采用Alamar Blue、倒置显微镜、荧光显微镜、扫描电镜、琼脂糖凝胶电泳、RT-PCR和Western blotting法检测不同体积分数的紫甘薯汁对SGC-7901、HO-8910和HepG2细胞的增殖抑制作用及诱导人肝癌细胞HepG2凋亡机制研究。结果:与对照组相比,体积分数5%和10%的紫甘薯汁对SGC-7901、HO-8910和HepG2细胞具有抑制作用,呈体积分数依赖性;作用HepG2细胞48h后,能观察到细胞皱缩和凋亡小体以及凋亡细胞典型的梯状DNA条带。RT-PCR和Western blotting法检测结果显示,紫甘薯汁可以诱导HepG2细胞中Fas、FADD、Caspase-3、Caspase-8和p53 mRNA表达水平上调和蛋白表达量增加,Caspase-3、Caspase-8、Caspase-9的活性裂解片段明显增高且Caspase-3酶活性显著提高。结论:紫甘薯汁体外对肿瘤细胞的增殖具有一定抑制作用且通过细胞表面死亡受体途径诱导HepG2细胞凋亡,同时p53在此凋亡过程中也起着重要的作用。     

鼓槌石斛毛兰素诱导人结肠癌Caco-2细胞凋亡

目的:研究毛兰素对人结肠癌Caco-2细胞增殖的抑制作用及其诱导细胞凋亡的分子机制。方法:采用SRB法检测毛兰素对Caco-2细胞增殖的抑制作用,用Hoechst33342染色法观察细胞的形态学改变,流式细胞术检测细胞的凋亡率和细胞周期;蛋白免疫印迹法(Western Blot)检测细胞凋亡相关蛋白Caspase-3的表达水平。结果:与对照相比,毛兰素能抑制结肠癌细胞Caco-2的增殖,且抑制率随着药物浓度与时间增加,呈剂量时间效应,48 h半数抑制浓度IC50为0.845μg/m L;毛兰素能诱导Caco-2细胞凋亡,并诱导细胞周期阻滞于G_2期;Caspase-3活性裂解片段表达增高。结论:毛兰素对肿瘤细胞的增殖具有一定抑制作用且通过线粒体途径诱导Caco-2细胞凋亡。     

金钗石斛脂溶性生物碱提取物诱导人结肠癌 HT-29 细胞凋亡

目的:研究金钗石斛脂溶性生物碱提取物对人结肠癌HT-29细胞生长的抑制作用及其诱导细胞凋亡的分子机制。方法:MTT法检测金钗石斛脂溶性生物碱提取物对HT-29细胞存活率的影响,Hoechst33342染色法观察细胞形态学变化,流式细胞仪检测胞内活性氧水平、线粒体膜电位、细胞周期和细胞凋亡率变化;蛋白免疫印迹检法测蛋白Caspase-3,9和胞内细胞色素C的表达。结果:金钗石斛脂溶性生物碱提取物能降低HT-29结肠癌细胞存活率,呈剂量和时间效应,48 h半数抑制浓度(IC50)为0.72 mg/m L;金钗石斛脂溶性生物碱提取物能诱导HT-29细胞凋亡,并诱导细胞周期阻滞于G2期;金钗石斛脂溶性生物碱提取物诱使线粒体膜电位降低,胞内活性氧浓度升高;激活型Caspase-9,3与胞内细胞色素C表达水平增高。结论:金钗石斛脂溶性生物碱提取物对HT-29结肠癌细胞的生长具有抑制作用并诱导细胞凋亡,其可能通过线粒体凋亡途径诱导细胞凋亡。     

高良姜素对肝癌细胞HepG-2的凋亡效应

以人肝癌细胞 HepG-2 为研究对象,探讨高良姜素对肝癌细胞增殖及凋亡的影响。研究不同浓度的高良姜素对HepG-2细胞毒性及形态学、凋亡率、细胞周期及线粒体膜电位、胞内钙离子稳态的影响。结果表明:5.4、10.8和21.6 μg/mL高良姜素使细胞增殖受到抑制,48 h光密度(optical density,OD)值分别为1.295、1.170、1.043,呈现典型的凋亡形态学变化,细胞周期阻滞于DNA合成前期(first gap,G1)。出现凋亡细胞且凋亡率均呈浓度和时间依赖性,48 h凋亡率分别为23.34%、33.15%、44.15%。细胞线粒体膜电位降低,空白对照细胞线粒体膜电位相对荧光强度为27.32,5.4、10.8和21.6 μg/mL高良姜素处理组分别为11.26、7.23、3.17;细胞内钙离子浓度增大,空白对照胞内钙离子浓度相对荧光强度为3.82,5.4、10.8和21.6 μg/mL高良姜素处理组分别为6.83、11.63、18.73;胞内钙离子稳态被打破。高良姜素可通过阻滞细胞周期进程,降低线粒体膜电位,打破细胞内钙离子稳态来诱导肝癌细胞HepG-2凋亡。     

巴豆醛诱导人支气管上皮细胞凋亡研究

为了评价卷烟烟气的危害性,研究了巴豆醛导致人支气管上皮细胞BEAS-2B死亡机制.即采用MTT法检测细胞存活率,化学发光法检测胞内ATP含量,流式细胞仪检测细胞凋亡率,流式细胞仪结合免疫化学检测线粒体细胞色素c,化学发光法检测caspase-9,caspase-3/7.结果显示,巴豆醛诱导细胞凋亡,且随着剂量增大,细胞由凋亡转向坏死.巴豆醛导致胞内ATP水平迅速下降,导致细胞线粒体膜电位下降,导致细胞色素c由线粒体释放至胞浆,激活caspase-9和caspase-3/7.结论:巴豆醛诱导细胞凋亡,且caspase级联酶参与巴豆醛诱导的细胞凋亡.     

薯蓣皂苷对HepG2肝癌细胞增殖的抑制作用

研究薯蓣皂苷对HepG2肝癌细胞增殖的抑制作用。不同浓度薯蓣皂苷干预HepG2肝癌细胞24h后,采用MTT法、Hoechst33258染色法、JC-1染色法和Western blot法检测细胞的增殖能力、线粒体膜电位水平、活性氧水平和Bax、Bcl-2表达。结果显示,2.00μmol/L薯蓣皂苷组对HepG2细胞的抑制率为41.69%,高于1.00μmol/L薯蓣皂苷组;薯蓣皂苷干预HepG2细胞后,细胞分布密度降低,出现变圆脱落死亡;升高ROS水平、降低MMP、抑制Bcl-2和上调Bax的表达,与对照组相比均有显著性差异。2.00μmol/L薯蓣皂苷组Bcl-2、Bax相对表达量分别为0.08、0.10。以上实验结果表明,薯蓣皂苷可明显抑制HepG2肝癌细胞的增殖能力,诱导其发生凋亡,其机制可能与其通过线粒体途径降低MMP,抑制Bcl-2蛋白的表达,上调Bax蛋白的表达有关。     

芡实壳醇提物抑制人胃癌SGC7901细胞和人肝癌HepG2细胞增殖并促进其凋亡

为明确芡实壳醇提物对SGC7901及HepG2细胞体外抑制作用及机制。该研究采用75%乙醇对芡实壳超声提取,采用福林酚法测定醇提物总酚含量,采用CCK-8法检测醇提物对SGC7901和HepG2细胞的增殖作用抑制率并计算IC50值,使用流式细胞仪检测细胞凋亡、细胞周期、细胞线粒体膜电位及胞内钙离子浓度。结果表明,醇提物对SGC7901和HePG2细胞具有增殖抑制作用,浓度为200 μg/mL的醇提物作用细胞48 h后,抑制率分别为92.63%和72.40%。细胞周期检测表明,浓度为200~800 μg/mL的醇提物可使SGC7901细胞阻滞于G0/G1期;浓度为50~200 μg/mL的醇提物可使HepG2细胞阻滞于S期。细胞线粒体膜电位测定表明,醇提物可使SGC7901和HePG2细胞线粒体膜电位下降且具浓度依赖性,醇提物浓度为200 μg/mL时,细胞线粒体膜电位相较对照组分别下降21.92%和53.81%。细胞钙离子浓度测定表明,醇提物可使SGC7901和HePG2细胞内钙离子浓度升高且具浓度依赖性,醇提物浓度为200 μg/mL时,胞内钙离子浓度相较对照组分别上升21.85%和14.14%。实验表明芡实壳醇提物可抑制SGC7901和HepG2细胞增殖并诱导其凋亡,其作用机制可能与细胞线粒体膜电位降低及胞内钙离子浓度升高有关。     

灵芝肽诱导人肝癌HepG2细胞凋亡的细胞学观察

目的：研究灵芝肽(Ganoderma lucidum peptides,GLP)在体外对人肝癌HepG2细胞增殖抑制及诱导凋亡的作用。方法：HepG2细胞用含不同浓度GLP培养基培养12、24、36、48、60h,GLP分为5个浓度梯度,分别为0.25、0.5、1、2、4mg/ml,采用噻唑兰(methyl thiazolyl tetrazolium,MTT)法观察细胞生长抑制作用,用可见光显微镜、荧光显微镜观察细胞形态学变化、激光共聚焦(laser scanning confocal microscopy,LSCM)观察细胞内钙离子浓度的变化。结果：MTT法显示灵芝肽能显著抑制人肝癌HepG2细胞的生长,且存在浓度及时间依赖性。镜下可见细胞出现典型凋亡细胞形态学改变：细胞染色质浓缩,细胞体积缩小、核固缩深染、细胞膜出泡、凋亡小体形成;LSCM观察到胞内钙离子浓度明显增加。结论：0.25～4.0mg/ml的GLP体外可显著抑制人肝癌HepG2细胞增殖,存在量效关系和时效关系,能诱导人肝癌HepG2细胞凋亡,并且提示细胞内钙离子浓度的升高可能是细胞凋亡的机制之一。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the